Virus makes oysters more expensive, harder to find

CAP FERRET, France - Thomas Catonnet listens for the tell-tale death rattle at his oyster farm in France's Arcachon Bay, as a falling tide exposes victims of a lethal virus ravaging the nation's 157-year-old shellfish industry.

"You smell a particular odor, and you hear the sound of shells," said Catonnet, 33, sorting baby oysters in a wooden shack near the end of a 12-mile sandbar that shelters the bay from the Atlantic Ocean west of the city of Bordeaux. "A putrid smell. Nobody understands it."

A herpes virus has decimated oysters along France's 3,410-mile coast for a fourth season, making the shellfish an ever-more exclusive treat for year-end holiday meals that account for half of the country's oyster sales.

Farm-gate prices for oysters have jumped 65 percent in three years because of the disease, said Goulven Brest, head of France's shellfish-growers committee. He frets that high prices, which help keep growers like Catonnet afloat, and fewer oysters threaten an industry with $823 million in sales in 2009.

"The consumer is losing interest in the product because we have less to market," Brest said. "We can't charge more. We've reached a price beyond which demand will plummet."

Retail prices for oysters in Paris have climbed to between $18.25 and $22 a dozen in some neighborhoods, from $15.65 and $18.25 a dozen in 2010, he said. Wholesale prices in October climbed 8.2 percent from a year earlier and 26 percent from two years ago, according to the National Institute of Statistics and Economic Studies in Paris.

The disease killing France's Pacific oysters first emerged in 2008. It mostly strikes oysters under a year old, according to research by the French sea-research institute, Institut Francais de Recherche pour l'Exploitation de la Mer.

Between 70 and 80 percent of France's young stock died this year, according to the institute. Identified as a variant of Ostreid herpes virus 1, or OsHV-1, the disease starts killing oysters when water temperatures reach about 61 degrees Fahrenheit.

"In 2008, researchers were stunned by the scale and distribution of the phenomenon," said Marion Le Foll, a spokeswoman for the institute.

"(The institute's) studies show there's a tremendous genetic diversity in Pacific oysters; we can't explain the mortality through a lack of genetic diversity," Le Foll said.

Oysters are typically left to grow for three years before they're shipped to markets and restaurants across France. Last year was the first in which the virus made a noticeable dent in sales.

France's oyster harvest plunged 38 percent in 2010 to 80,000 metric tons from about 130,000 tons a year earlier, according to the shellfish-growers committee. Production is little changed this year, according to Brest.

The death of young oysters in Arcachon Bay, whose sandy beaches and sunny weather have attracted vacationers since the 19th century, is a particular concern. The basin produces about 70 percent of the nation's naturally grown oyster spat.

The Pacific oysters in Arcachon Bay, introduced from Japan in the 1970s, spawn billions of eggs twice a year. In summer, they take about 18 days to develop into larvae, says Christian Lapegue, an oyster farmer on the bay.

Farmers place larvae collectors in the bay that are taken out of the water from November to February. The baby oysters' death becomes apparent by February, said his son Yannick.

"You don't see the same thing from one oyster grower to the next," the 37-year-old said. "It depends on the location."

The industry is in a vicious spiral, Brest says: With smaller quantities available, the number of retail points will shrink after the festive season because the oysters are too expensive. That in turn means consumers will see less of the shellfish, which may bring down demand and prices.

"That could cost us very dearly," Brest said. "If prices fall again, it will be the whole industry that dies."